Centrifuge devices and methods of the present general nature are known to the art. These devices and methods are characterized by their ability to separate finely-divided particulate material from a suspending liquid, where the particulate material is to be substantially recovered and/or where the particulate material must be separated or washed or the like in an isolated environment. Thus, devices and methods of this nature have their greatest utility in connection with the separation and/or washing of solid blood components from whole blood or from a liquid blood fraction. The present invention is likewise applicable to such devices and methods, and thus, while the present invention has broader utility than the separation of blood components and extends to the breadth indicated above, the invention will be principally hereinafter described in terms of the embodiment of separation of solid blood components, for the sake of conciseness.
In prior co-pending application Ser. No. 714,651, which is a divisional application of Ser. No. 513,509, now U.S. Pat. No. 3,982,261, it is noted that human blood obtained from donors often contains unwanted contaminants such as toxins, viruses, medicants, bacteria and glycerine. These contaminants render that blood unsuitable for direct transfusion. The art has proposed various devices and methods for separating and washing the blood to remove those unwanted contaminants. The more accepted devices and methods to accomplish the foregoing are based upon centrifugal separation of the red blood cells from the blood fluids with a subsequent counter-flow washing of the blood cells to remove the contaminants. For purposes of the present specification and claims, the term "blood cells" is defined to mean all solid blood components, including red blood cells, leukocytes and platelets ("buffy coat"). After the blood cells have been adequately washed, they are removed from the devices, often by re-suspending in a suitable liquid, such as a sterile salinic solution, Locke-Ringer solution or human serum albumin. The cells are aspetically transferred from the devices into a sterile package. U.S. Pat. No. 3,347,454, issued to the present applicant is representative of this art. An improvement in this art is also provided by U.S. Pat. No. 3,561,672, issued to the present applicant, wherein disposable receptacles are provided which can receive a plurality of units of blood for washing in a single centrifuge operation. These disposable receptacles avoid the necessity of a thorough cleaning of the centrifuge after processing each donor's unit of blood. The operation of this device is described in some detail in Schlutz and Bellamy, Continuous Flow Cell Washing System, TRANSFUSION, Vol. 8, No. 5, Sept. Oct. 1968, and a pre-packaged combination of two receptacles, associated seal devices and conduits is described in detail by Schlutz and Bellamy in A Disposable Counterflow System for Washing Erythocytes in a Centrifugal Field, Proc. 12th Congr., Int. Soc. Blood Transf., Moscow 1969 Bibl. Haemat, No. 38, Part II, pp. 350-358 (Karger, Basel, 1971). Thus, the art has available considerable details regarding the operation and mechanical construction of centrifuges of the present nature as well as associated equipment for such centrifuges and those details will not be repeated herein. The entire disclosures of the above noted patents and publications are incorporated herein by reference and relied upon for the aforementioned details.
In application Ser. No. 714,651, a device and method are described where the efficiency of washing of blood cells is substantially increased in a centrifugal operation. That device includes an enclosure for enclosing liquid suspended blood cells wherein a plurality of angularly shaped blood cell receiving means are evenly spaced about the periphery of the enclosure. Each blood cell receiving means has at least one pair of opposite wall portions which converge toward the longitudinal periphery of the enclosure and form a locus of maximum centrifugal force in the rotating enclosure at the apex formed by the juncture of the converging wall portions. A conduit is disposed in the angularly shaped receiving means and terminates at or near the locus of maximum centrifugal force. An injector moves suspended blood cells into the enclosure and removes separated and washed cells from the conduit. Appropriate seal means provide for the enclosure means to be rotated about its vertical axis while maintaining a liquid-tight seal. The liquid suspended blood cells flow through the injector and into the enclosure and distribution of the suspended blood cells about the enclosure is accomplished by rotation of the enclosure. With further rotation the blood cells are separated and compacted in the angularly shaped receiving means. A wash liquid is then flowed through the conduits and the wash liquid therefore enters each receiving means at the furthest peripheral point and passes back through the compacted blood cells, thus, insuring complete washing of the blood cells. After the washing is completed, the blood cells may or may not be suspended in a suitable fluid, e.g. a salinic solution, and flowed out of the apparatus via the conduits.
As can be appreciated from the foregoing, the primary function performed by these prior devices is the separating of all of the blood cells from the suspending liquid, washing all of the blood cells, and then removing all of the blood cells from the devices. Thus, these devices do not function to effect any separation of the various blood cells, e.g. red blood cells from formed elements (platelets, etc.) and leukocytes or to recover so separated red blood cells.
However, in certain circumstances it would be a decided advantage in the art to separate red blood cells from other cells, i.e. the other formed elements, and provide such separated red cells substantially free of the other formed solid blood elements, e.g. the leukocytes and platelets, and, further, recover such red blood cells in a non-suspended form. Such recovered red blood cells are of considerable value in correcting the anemia of patients who are candidates for tissue transplants or for patients who require continued replenishment of red cells. For example, if whole blood is given to replenish the depleted supply of red blood cells, often the required volume of whole blood during a period of time exceeds the total liquid volume which can be contained in the body circulatory system without the risk of causing congestion in the kidney, heart and lung (hypervolemia). Additionally, when whole blood is given only for the purpose of replenishing red blood cells, the unnecessary additional leukocytes and platelets which the patient receives can produce severe, perhaps, fatal reactions. For example, in transplant patients, the transfusion of leukocytes may initate transplant rejections. When blood cells are separated and/or washed according to the prior methods an inconsequential portion of the leukocytes and platelets are removed and the risks of severe reactions or transplant rejections remain.
As can be appreciated, therefore, the prior devices and methods are not satisfactory for use in treating diseases and conditions which primarily affect the red blood cell population. It would be, however, of decided advantage in the art to provide devices and methods for separating red blood cells and providing such cells which are substantially free from leukocytes and platelets and which cells can be recovered in a substantially non-suspended form. Such methods and devices, of course, must be capable of functioning in a practical manner to recover practical amounts of red blood cells. Additionally, such devices and methods must be capable of recovering those red blood cells in such a manner as to not introduce foreign contaminants such as airborne bacteria, solid particulate matter and the like. Of even further advantage would be the ability of such devices and methods to recover the red blood cells in a device which is pre-sterilized.